Aerospace Metal 3D Printing: Materials, Machines and Methods

In mid-2014 Vice Adm. Dunaway, then commander of the Naval Air Systems Command (NAVAR), challenged the AM/Digital Thread Integrated Product Team (IPT) to “operationalize” additive manufacturing (AM) across NAVAIR.

The original goal was to demo a flight-critical part in three years; they are actually going to accomplish it in 14-18 months. NAVAIR plans to fly its first additively manufactured metal part on a V-22 Osprey tilt-rotor aircraft this spring. The part, made of the titanium-aluminum alloy Ti-6Al-4V, or Ti64, is considered flight-critical.

Photo: http://3dmpmag.com

Forays into metal 3D printing for aerospace have relied on powder-bed fusion technology, which uses high-powered lasers to trace a computer-generated 3D design on a thin layer of metal powder.Different manufacturers use slightly different variations of the technology. Examples include selective laser sintering (SLS), selective heat sintering (SHS) and selective laser melting (SLM). A trademarked version, called direct metal laser sintering (DMLS), developed by EOS GmbH, of Germany, is the process used by NAVAIR to print its demo parts.

Another powder-bed fusion technology, called electron beam melting (EBM), was pioneered by Swedish company Arcam. EBM employs a high-temperature electronic beam, rather than a laser, to melt the metallic powder.

Because metallic powders are expensive and heavy, powder-bed fusion technology is limited in the part volume it can print, though each new generation of printers seems to accommodate larger and larger builds.

3D printing has become a game changer for many aerospace OEMs, by drastically reducing the time and cost to develop prototypes and tooling.